Crankcase for internal-combustion engines



.Jano 239 3.953 w. HARPER CRANKCASE FOR INTERNAL-COMBUSTION ENGINES Filed Jan. 25, 1945 5 Sheets-Sheet l nA. ,U m W E a Ww n I 6 Jam, 23, E951 w. HARPER 2,539,132

CRANKCASE FOR INTERNAL-COMBUSTION ENGINES Filed Jan. 25 1945 5 Sheets-Sheet 2 ern".

1 u um ,NIH

lm W Q Jan. 23 MSE w. HARPER cRANxcAsE FOR INTERNAL-COMBUSTION ENGINES 5 Sheets-Sheet 4 Filed Jan. 25, 1945 INVENTOR. @Jai-7W Jam 23, 19M W. HARPER cRANKcAsE: FOR INTERNAL-COMBUSHQN ENGINES Filed Jan. 25, 1945 5 Sheets-Sheet 5 rmember andthe Walls.

Patented Jan. 23, 1951 STATES TENT OFiTiQE CRANKCASE FOR INTERNAL-GOMBUSTIGN vENGINES This invention relates to crank cases and'aims to provide an improved crank case for'internal combustion engines. t

.The heaviest part of an ordinary internal com- ;bustion engine is the cast engine-base or crank .case which supports the cylinders and houses the crank shaft and provides Asupporting bearings for it. I have discovered that it is possible to effect a radical reducticncin the weight of internal combustion engines by substituting for the castings of which the engine-base or crank case is ordinarily made. a fabricated structure 'for supporting the cylinders andv crank shaft vbearings which, while using very much less metal than the ordinary castings, attains the required strength and rigidity.

The ordinary crank case or engine-base consists of a casing having transverse end walls to support the shaft bearings, and transverse interior bearing-supporting walls in the case of a multi-cylinder engine. In order that the crank shaft may be assembled with the crank case initially Vand in order 4to permit removal and repair of the crank shaft, the crank case is made of two separate castings meeting and bolted together on a longitudinal plane ofthe crank case which cuts the bearing-supporting walls so as to permit removal of the crank shaft and its bearings by separating the .two castings.

V.The fabricated crank'case .which I have invented departs radically from this conventional construction. It consists of a continuous Vtubular member open at its ends,.and transverse walls which are separate from the tubular member and are compressivelygrippedin it. vThetubular member supports the engine cylinders and the transverse walls support the crank shaft bearings. The walls are gripped so firmly in the tubular member as to make the entire crank case in effect a single integral member after it has. been. assembled with .the crank shaft within it. The transverse .walls may nevertheless be removed endwise. from the tubular member by releasing tsgrip on .them by .shrinking the walls `and expanding thetubular member. For Vthis 1 purpose,.means araplovided for creating a wide difference .in temperature Abetween .the vtubular It is .thus .possible vto insert transverse walls with the crankshaft endwise into the tubular.member when the crank case is. first assembled,and to removethe walls and the crank shaft endwise whenever examina- 'tion orrepairof the crank shaft isrequired.

The tubular member .of the .new `crank case,

, inthe construction which I iind mostdenrable.

is double walled having an inner sheetusteel shell formed to withstand compression and an outer sheet-steel shell Vformed to withstand tension. The inner shell has the form of a cylinder. The outer shell has a wall to which the engine cylinders are attached. This is spaced frena-and of less width than the diameter of, the inner shell. F'lat walls extend from the spaced wall in planes tangent to the inner shell and carry the tension strains of the engine cylinders to the inner shell in such manner as to produce compression strains on it which it is well adapted to withstand. The inner and outer shells have diierent natural periods of vibration owing to their different shape and Size, so that any vibrations or" the natural period of either of them is damped by the other.

A further feature of my invention consists in suspending the crank case at its ends from rigid supports so that it may react to the torque of the engine in a semiflexible manner. Each end of the crank case. is provided with a round bearing which may be engaged by a complementary bearing fixed to a rigid plate'so that-the crank case may rotate about the axis of the crank shaft. This rotation is limited by a set of spaced projections 4fixed to the ends of the ycrank case and resilientlyengagedby the-supporting plates.

Other features and .advantages of my invention will bedescribed in connection witha description ofthe speciccrank case embodying my invention which is illustrated in the accompanying drawings, in which:

Fig. 1 is a perspective view of the inner and outer sheet-steel shells of the tubular member of the crank case;

Fig. 2 is a perspective view of the tubular member;

Fig. 3 is an end elevation of the crank case support;

Fig. 4 is a fragmentary section along'the axis of the tubularmember with the transverse lend walls in position for insertion;

Fig. 5 is a fragmentary side elevation of the crank shaft showing .one of the intermediate transverse walls mounted on its bearing;

Fig. 6 is a sectional elevation on the axis of the crank case, showing one end of the crank case with the crank shaft assembled therein;

Fig. 7 is a similar View of the other end of the assembled crank case and crank shaft;

Fig. 8 is a transverse section, on a slightly reduced scale, along the line 8*-8 of Fig. 6;

Fig, 9 isa side elevation of one end of the crank case partly broken away;

Fig. 10 is a transverse section of a stamped disc used in the fabrication of the transverse walls and the braces for the tubular member;

Fig. 11 is a transverse section of a brace for the tubular member; and

Fig. 12 is a transverse section of a side plate of one of the transverse walls.

rlhe crank case illustrated in the drawings is intended for use in connection with a multi-cylinder internal combustion engine cf the opposedpiston type. While my new crank case possesses special advantages for such an engine, it may readily be adapted to any type of internal combustion engine.

The crank case consists of a tubular member A open at its ends and separate transverse walls B includingr end walls Bl, B2 and intermediate Walls B3. It is suspended at its ends from supports C.

The tubular member A is a double wall structure including an inner shell Al and an outer shell A2.

The inner shell AI is a steel cylinder formed by rolling a steel sheet and welding its abutting edges. It is provided internally with hollow flat reinforcing collars A3 consisting of circular bands A4 smaller than the cylinder and supported on V-shaped transverse braces A5 which are welded to the cylinder and its bands. rEhe two reinforcing collars A6 at the ends of the cylinder are of slightly diierent construction,4 as the outer edges of their bands All are held by the end plates A7 hereinafter mentioned instead of by V -shaped braces. As hereinafter explained, the reinforcing collars provide means or gripping the separate transverse walls B. Slots A8 for connecting rods are provided in the shell Ai between the reinforcing collars, and a series of circular access openings A9 is provided along the top of the shell.

The outer shell A2 is also formed from a sheet of steel which is bent into the form of a tube and has its abutting edges welded together. The outer shell A2 has a pair of opposite walls AH which are spaced outwardly from, and are of less width than the diameter of the inner cylindrical shell Ai, and pairs of walls A2 which connect the walls All to the inner shell AI and extend tangentially to the inner shell AI to provide tension members transmitting the pull of engine cylinders mounted on the walls AI I to the shell AI in such a Way as to produce compression strains on that shell. lhe spaced walls Ail are provided with a series of round openings Alli adapted to receive sleeves A55 for the engine cylinders. Along the top of the outer shell A2 is a series of round openings ASS registering with those in the top of the inner shell Ai.

The inner and outer shells AI, A2 are welded together along their lines of contact and are connected by sleeves AIS, tie members AI'I and AIS, and end plates A'l which are welded to both of them. Covers AIS are provided for the access openings A9.

rIhe sleeves AEE have external flanges A22 at one end. They are inserted in the holes Alt in the outer shell A2, and the inner edges of the sleeves are welded to the inner shell AI. The flanges overlie the outer shell A2 at the periphery of the opening AM and are provided with bolt holes A2! extending through the outer shell A2 for attachment of the engine cylinders.

The transverse tie members All (shown in Fig. 9) lie between the spaced portions of the inner and outer shells Al, A2 and are Welded t0 bOth `-hells and to the sleeves AI 5.

The end plates A7 have outer peripheries conforming to the cross-section of the outer shell A2 and contain circular holes of a diameter less than that of the inner shell Ai and equal to the inner diameter of the circular bands A4 of the internal reinforcing collars A6. The end plates are welded to the end edges of the outer shell A2, of the innel` shell AI and of the bands A4 of the reinforcing collars A6 at the ends of the inner shell AI.

The end Wall BI, as best shown in Fig. 6, is fabricated from a steel tube B4 to which are welded side plates B5, B6 and radial, generally lJ-shaped reinforcing members B?. After those parts have been welded to each other, cylindrical bands B8 are welded in place. The side plate BE is of the same diameter as the inner shell AI and is conneeted to the housing iG fol` ball bearings II through conical plate B9 which, with the sleeve BS, supports that housing.

The end wall B2, as best shown in Fig. 7, is fabricated from a steel tube Bi l to which are welded side plates Bit, BI5 and radial7 generally U- shaped reinforcements BIE. After those parts have been welded to each other, band B I 1 is welded in place. Side wall B25 is of the same diameter as the inner shell Al and is connected with sleeve Bil by reinforcing plate Bill. The sleeve Bil provides a housing for the ball bearings I4 and is connected also with the housing l5 for gears i6, El and i8 which are adapted to drive the cam shaft of the engine (not shown).

Each of the intermediate walls B3 consists of a pair of hollow semi-circular discs B2I connected by bolts B22 and communicating with each other through openings B23. Tubes B2Ll provide access to bolts B22 (Fig. 8). The discs B2I are fabricated from steel castings B25 to which are welded side plates B26, radial, generally U-shaped reinforcing members B2? and end plates B23. After those parts have been welded to each other, band B29 is welded in place. An oil channel B30 extends through disc B2I to provide lubrication for the bearings. In the fabrication of the walls B, the nal closing welds should not be made until after the balance of the metal in the assembly has been permitted to solidify. As the assembly cools, the U-shaped members B27 give sumciently to prevent shrinkage cracks.

The side plates B26 for walls B3, and the V- shaped braces A5 are preferably fabricated as follows: A disc of of sheet steel is given a dish shape, as `by means of stamping, to provide anges A22 and a central portion BSE (Fig. l0). The flanges A22 are severed from the central portion B3! and a pair of such anges are welded to each other to form the V-shaped braces A5 (Fig. 1l). The side plates B26 are formed from the central portion B3i by making an axial opening therein (Fig. 12).

The dimensions of collars A3, A6 and of the transverse walls B are such that the internal diameter of the collars is slightly less than the external diameter of the wals when their temperatures are substantially the same, but when the collars are approximately 200 F. hotter than the walls there is a slight clearance between them. In order that the transverse walls B may be fitted within their respective collars, means are provided for circulating a heating medium through the collars and a cooling medium through the Walls:

Internally threaded discs A22 are inserted in holes drilled through the shells AI, A2 and provide passageways communicating with the in- 'teri'ors of fthe collars.

*braces -A f are provided lwith openings A23. vternally threaded tubesB32 are inserted in holes linthe-bands B3, Blr'l and B29 and are lwelded to rthose bands. Bolts .B33 are provided for those 'The inner :legs of 'the tubes. To permit access to the 'bolts B33 after 'the crank shaft and crank'casehave been assem bled, conduits 'Bfi extend through the shells Ai,

A2 to'holes in the collars A3, A5 which are adapted to register ywith the threaded bores in 'hot oil, which may :now to the interiors of the collars A3, A6 through vthe passageways in discs A22 and throughthe openings A23, is 4circulated 'Within those collars Ato heat and expand them,

After-the desired difference in the temperatures of those collars and walls is attained, the crank shaft is thrust endwise into the cra-nk case so that the intermediate Walls B3 are properly positioned in their respective collars A3. Walls Bl, B2 arezthen'rsimi'arly slid over the ends of the crank shaft until they are properly posi tioned in their respective collars A6.

After the crank shaft and crank case have been placed in proper position, they arefastened .I

by bolts B33, B355, and the temperatures of the collars and transverse Walls are permitted to return to normal. Theconsequent shrinkage of the-collars A3, A6 and expansion oi the transverse walls Bcauses thecol'ars to compressthe Walls, and, since thecollarsare'prcvented by the walls from fully contracting, they are kept under tension. As a result, the collars exert a powerful grip on the walls and an exceptionally rigid and strong construction is provided.

The crank shaft may be removed from the crank case by circulat'ng a heating medium through the walls B and a cooling medium through the colars A3, A6 until there is a clearance between them. Then, when the bolts B33, B35 are removed, the walls may be slid out of their collars.

The support C for the crank case includes a pair of rigid p'ates CI. A cylindrical band B3'i having an internal reinforcing ange B33 is welded to the side plate B5 of wall Bi. A like band B39 having an internal reinforcing ange B40 is we'ded to the end plate BH3 of wall B2. The bands B3?, B39 form bearing members which may be engaged by circular flanges C2 tired to the plates Cl, so that the crank case may rotate about the axis oi the crank shaft. Adjustable rubber bushings which are mounted on tubes B! fixed to the crank case and projecting beyondthe end plates are adapted tc enter tubes C3. extending from the inner faces of the end plates C! and resiliently iimit rotation of the crank case. As a consequence, the crank case is held in accurate alignment with respect to the crank shaft but is permitted a limited amount of rotation about the axis of the crank shaft and expansion or contraction. due to heating or cooling of the structure Wll not develop undue stresses at the mounting points.

It will be apparent to those skilled in the art vthat variouschanges and modications may be made inthe specific embodiment of my invention described above without departing from the sprit of my invention as dened in the following claims.

'What I claim' is:

1. A crank case for internal combustion engines, comprising a tubular member, removable transverse walls for said tubular member, and

internal collars iixed in said tubular member `around. said transverserwals and adapted to exert a compressive grip on said walls.

2. A crank-case lfor internal combustion engines comprising the combination with a tubular member, of internalhollcw collars fixed in the tubular member and having openings for the introduction of-a heating medium, and removable hollow transverse walls surrounded by the collars andadapted to be vgripped conipressively by said rec'illars and having openings for the introduction of a cooling medium.

3. A crank case for internalrcembustion enm gines comprising the combination .fith a tubular member having open ends, oivholow collars hired in the tubular member and having openings to permit circulation of a heating medium therein,

and aset'o'i vreinovable hollow transverse walls includingapair of lend wallsand a diametrically 'split vintermediate wall, sad walls being sulroundedby/ said colars and adapted to be gripped compressively by the collars and having' openings to permit circulation of a coolingmedium therein.

4. A crank case for internal combustion engines comprising the combination with a tubular membergof hollow collars in the tubular -member and each having-a passageway from its interior to the exterior of the tubular member, removable hollow traneverseiwalls'having open- -ings thereinand surrounded by said collars and adapted to be gripped corni essively by the collars, and conduits'extending rom the exterior of the tubular member through 'the collars to register w'th the openings inthe transverse walls to permit introduction of a cooling A'5. A- crank case for internal combustion engines comprising the combination with an inner cylindrical shell, of an outer shell having a base for engine cylinders and a pair of opposite walls attached to the cylindrical shell and extending tangentially therefrom to said cylinder base.

6. A crank case for internal combustion engines of the opposed-piston type comprising the combination with an inner cylindrical shell, of an outer shell having opposite walls spaced outwardly from the inner shell and of less width than the diameter of the inner shell to provide bases for engine cylinders and walls connecting said spaced walls and embracing the inner shell.

'7. A crank case for internal combustion engines comprising the combination with a 'cylindrical shell, of a base for engine cylinders and tension members connecting said shell with the cylinder base.

8. A crank case for internal combustion engines of the opposed-piston type comprising the combination with a cylindrical shell., of a pair of opposite bases for engine cylinders spaced outwardly from the shell and of less width than the diameter of said shell and tension members connecting the cylinder bases and embracing the shell.

9. A crank case for internal combustion engines comprising the combination with a rein- 'forced cylindrical shell adapted to withstand compressive strains, of a cylinder base, and tension members attached to said shell and extending tangentially therefrom to the cylinder base.

10- A crank case for internal combustion engines comprising the combination with an inner cylindrical shell, of an outer shell having a wall spaced outwardly from the inner shell and adapted to provide a base for engine cylinders, and a pair of walls welded to said inner shell and extending tangentially therefrom to the cylinder base, .and sleeves extending from the cylinder base to the inner shell and welded to both of them.

11. A crank case for internal combustion engines comprising the combination with a cylindrical inner shell, of a shell having opposite walls spaced outwardly from the inner shell and of less width than the diameter of the inner shell to provide bases for engine cylinders and walls connecting said spaced walls and embracing the inner shell, and plates connecting the corresponding ends of the inner and outer shells and welded to both of them.

12. A crank case for internal combustion engines comprising the combination with a cylindrical shell, of a shell having a, wall spaced outwardly from said cylindrical shell to provide an engine cylinder base and a pair of opposite walls welded to the cylindrical shell and extending tangentially therefrom to said cylinder base, and internal reinforcing collars welded to the cylindrical shell.

13. A crank case for internal combustion engines comprising the combination with a cylindrical shell, of a base for engine cylinders, tension members connecting the shell with the cylinder base, removable transverse walls for said shell, and means fixed in the shell for compressively gripping said walls.

14. A crank case for internal combustion engine comprising the combination with an inner cylindrical shell, of an outer shell having a wall spaced from the inner shell to provide an engine cylinder base and walls connected with the inner shell and extending tangentially therefrom to the cylinder base, hollow collars fixed in the inner shell, a passageway through the inner and outer shells to the interior of each collar to permit introduction of a heating medium, removable transverse hollow walls surrounded by said collars and adapted to be gripped compressively by the collars and having openings in their peripheries, and conduits adapted to register with said peripheral openings and extending through the shells and collars to permit introduction of a cooling medium in said walls.

15. A crank case for internal combustion engines having a round bearing and a set of spaced projections at each of its ends, and a support for said crank case having means engaging said bearing to support the crank case while permitting axial rotation thereof and resilient means adapted to limit rotation of the crank case.

16. A crank case for internal combustion engines comprising a sheet-steel cylinder adapted to house crank shaft bearings, spaced tubes attached to said cylinder and projecting beyond its ends, and a support for each end of said crank case having a cylindrical flange adapted to erigage and support an end of the crank case while permitting it to rotate about its axis and resilient means adapted to limit rotation of the crank case.

WILLIAM HARPER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 940,650 Herreshoff Nov. 16, 1909 1,098,341 Alley et al May 26, 1914 1,114,554 Utz Oct. 20, 1914 1,820,069 Herr Aug. 25, 1931 1,839,850 Hodgkinson Jan. 5, 1932 1,933,246 Edwards Oct. 3l, 1933 FOREIGN PATENTS Number Country Date 296,337 Great Britain Aug. 27, 1928 

